He wrote:

all records inserted by tr2 are not updated if tr1 is e.g. snapshot

or during tr1 update there are inserts.

I wrote: 

 

Actually, that's not true.  

 

And I was wrong and lazy.  Should have tested it.  Records inserted by one

transaction will not be affected by an update by another concurrent transaction. 

My apologies.

Best regards,

Ann